These cords, of textile or metallic nature, are usually employed in the manufacture of tires in the form of plies containing mutually parallel threads or wires and making an angle in relation to the circumferential direction, or bundles of cords, which are deposited directly on the tire blank during production. The cords are obtained by combining individual threads or wires that are assembled together in successive layers and twisted so as to give the final cord the desired mechanical strength and elasticity properties.
The invention relates to cords, essentially metal cords, in which a rubber compound is injected between the layers of wire so as to give the cord additional wear resistance and corrosion resistance properties. The cords are obtained by a combination of assembling and rubberizing means so that the rubber compound is trapped within the structure of the cord.
A process of this type is described for example in the publication WO 2005/071157.
However, it turns out that, during implementation of this process, elements of rubber compound remain on the surface of the cords. These protrusions present on the surface of the cords constitute undesirable aggregates because of the disturbance that they introduce into the downstream cord production processes. Furthermore, they constitute localized areas of additional thickness of compound on the back of the reinforcing cords, and make it more difficult to control the thicknesses of rubber compound deposited on these cords during the calendaring operations.
The publication WO 2009/083213 describes for example an improved process which makes it possible to reduce the protrusions in question in a cord of 3+N type. In remoter technological fields, the publication FR 2 925 198 describes a method and a device for checking the proportion of hydrides present in a metal alloy, such as an alloy used for cladding nuclear fuel rods, and comprising image processing means, but the construction thereof is not appropriate to solving the problem addressed. Likewise, the publication US 2001/0037694 describes a method of checking the wall thickness of stents used in medical applications, which also involves image processing means for selecting the measurement areas.